Influenza is a constant and serious threat to public health. Each year, influenza associated illness leads to approximately 200,000 hospitalizations and 36,000 deaths in the United States. From a national impact perspective, the total economic costs in 2010 from influenza were estimated at $29 Billion. Antiviral therapy for influenza is effective, when given as a treatment or given for prophylaxis in a timely manner. Several studies conclude neuraminidase drugs reduce the duration of symptoms. Tamiflu and Relenza are both 80% effective in prophylaxis against seasonal flu. When treating patients with influenza, it is recommended that the patient start therapy within 48 hours of symptoms and smaller delays are better. Prompt diagnosis and initiation of the antiviral therapy leads to the best patient outcome.
Based on widespread resistance to the M2 channel blockers, it is not unreasonable to speculate that widespread use of neuraminidase inhibitors may ultimately lead to an emergence of their resistance in seasonal or pandemic influenza virus. A number of neuraminidase inhibitor resistant mutants have been identified during clinical studies. In a three-year period of surveillance, eight virus variants with a >10-fold decrease in susceptibility to oseltamivir were isolated. These findings should cause pause when considering the mass distribution of neuraminidase inhibitor-based drugs for the management of seasonal flu. In 2010 the WHO held the first global consultation on antiviral resistance in Hong Kong, following the emergence of transmissible oseltamivir-resistant influenza virus during the 2007-2008 winter season and detections of oseltamivir resistance in HSN1 and pandemic influenza H1N1 (2009). A key outcome from this consultation was the requirement for formal state reporting of antiviral resistance to influenza, either in clinical settings or as part of national surveillance. Moreover, some antivirals like oseltamivir cause adverse events making it important to only prescribe when required. Coverage for the various antiviral drugs can vary with provider and have different costs to the patient. The physician has a responsibility to only prescribe what is needed. While cost is secondary to effectiveness, if a patient can get by with a less expensive drug, the physician has an obligation to make the patient aware of the option. Accordingly, there is an unmet need for point of care tests that can provide diagnosis of a specific strain to avoid adverse events, slow down the evolution of drug resistance, and create a savings to the patient and the U.S. healthcare system.